Process of making indoxyl, &amp;c.



'35 glycin a-liquid mixture of alkali, such as is:

AUGUSTUS srs cntna, OF 'BASEL; SWI ZER AN ASSIGNOR TO THE FIR-M 0F Blast 4 I enEMIoAL .WoBKs, on BASEL, SWITZERLAND.

. rnocnss' or INDOXYL, 8w.

Specification oi! iietters Patent.

Patented July as, 1908.

To all whom it may concern:

-Be it'known that I, AUGUSTUS BISCHLER, doctor of philosophy and chemist, a. subject of the Emperor of Russia, and residentc of Basel, Switzerland, have'inventedia new and useful Process for the Manufacture of -Indoxyl, its Homologues, and their Derivatives, of which the following is a full, clear, and exact s' ecification.

In my nited States Letters Patent No 776884 dated December 6,- 1904, a process ,for the manufacture of indoxyl, its homo-- I logues and their derivatives is described, which consists in adding an alkali salt of an arylglycin to a heated mixture of caustic potash and metallic sodium, and, after the arylglycin has entered into reaction with part of the sodium, forming a. sodium arylf amin compound, continuing to heat with an. addition of a primary or secondary aromatic amin. In working this 'rocess, I' have; found that it may be mo ified in that the aromatic amin may first be added to the heated mixture-of caustic potash and metal? lic sodium, and only when the reaction with;

j the sodium, "forming. h mr compound, has occurred,

' lent to the sodium-aryla an arylamin is the ary glycin salt added to the mass and the heat ng con l This neW process which constitutes thej present inventionoflers certain advantagesi}:

scribed inthe aforesaid s eoification; the op'-'= eration presents no d' culties whatever}; If, however, for the treatment of the arylg obtained in a direct manner by dehydrating" -a-mixture of alkalies, and metallic sodium are employed, it is not possible to -add the arylglycin all at once, as the development of" hydrogen causes the mass to foam violently.

To prevent it from foamin over it is indispensable in this case to a d the arylglycin' slowly in quite small portions; 'if the tem erature durin this proceeding. is kept so ow that no in oxyl is formed, a part of the glycin becomes decomposed in consequence of the prolonged heating and the subsequent yields'of indi o are less good. If, however, e allowed to react first on a melted mixture of alkali and inetallicjs0- dium, a quantityof arylglycin salt, equivamin compound-may afterwards be added all an, 'ebullitio'n of the liberated amin, and no into '180 parts of at once, only causing foaming. Theamin is again bound by the sodium present in the mixture.

--r .The followin :examplhsiillustrate. 'fvention','zthe i arts being by; weight I 5 Example melted mixture of 120 parts of caustic potash and 80 parts of-caustic' soda placed ina boiler provided with an agitator, are first added 18.8 parts of metallic sodium and when the temperature of the mass is about 220-22 5 (l, 19 parts of anilin are introduced, a long reflux condenser being used;, when the anilinis bound, 37.8 parts of potassium salt of phenylglycin are added through a widetube in such a manner as to prevent any of the, liber .ul i

ated anilin from being wasted. If some of the anilin should distil over, it must be oured back. When the anilin is again 'liound, the heating is continued at a temperature of-225-235 0., until the formation of the indoxyl is completed. The mass is dissolved in water, the indoxyl converted "To .a heated, dehydrated .intofindigovby the introduction of air, the.

.indigo is filtered, washed first with water, .then' with hydrochlori'c acid, again with water, and finally with alcohohanddried. 1 Example II. At a temperature of 230 C. 13.8 parts of metallic sodium are introduced a dehydrated mixture of caustic sodaand caustic potash in equimo lecular' pro ortions, and at about 220 C. 23. parts of ethylanilin are added, a large reflux condenser being used. After the amin is bound by the sodium, 37.8 parts of potassiu'msalt of'phenylglycin are added to the ;;mass and the ating is continued at 230-240? C. until test portionstaken from the mixture show that the quantity of indoxyl no longer increases. The indoxyl is converted into indigo, and the indigo isolated, as indicated above.

Instead of 1 molecular 1proportion of amin,-

from two to three molecu ar proportions may be allowed to react on the mixture of caustic potash and 3 molecular proportions ofmetal- 0 sodium and the after the formation of the sodium-arylamin has occurred, but the amin which is already liberated by the introduction oi the glycin and through the subse uent heating process, must be distilled off. 11 this case, especially when using 3 molecular proportions of amin the formation of indoxy must be performs at a temperature exceeding that indicated in the above examples.

ioo

phenylglyoin can be added ioa What I claim is: 4

1. In the process for the manufacture of indoxyl, its homologues and their derivatives by heating the arylglycins and their derivatives with caustic alkali and a sodium arylamin, causing an aromatic amin of the anilin series to act first on a heated mixture of caustic alkali and metallic sodium, then adding the glycin derivative and continuing to heat until the formation of the indigo leuco-derivative is complete, as described.

2. In the process for the manufacture of indoxyl, its homologues and their derivatives by heating the arylglycins and their derivatives With caustic alkali, a sodium arylamin and metallic sodium, causing an aromatic amin of the aniliu series to act first on a heated mixture of caustic alkali and metallic sodium, then adding the glycin do rivative and continuing to heat until the formation of the indigo leuco-derivative is complete, as described.

In witness whereof I have hereunto signed my name this 14 day of March 1908, in the presence or" two subscribing Witnesses.

AUGUSTUS BISCHLER. 

